Webby thoughts, most about around interesting applications of ecmascript in relation to other open web standards. I live in Mountain View, California, and spend some of my spare time co-maintaining Greasemonkey together with Anthony Lieuallen.

2010-01-13

I just ended up needing to do subversion keyword expansion on a bunch of files in a subversion repository I track with git, but git-svn doesn't do that kind of thing. So I hacked up a tiny shell script I called git-svn-keyword-expand, which looks like this:

Just feed it a list of files, and it'll update them in place to whatever current revision they are at. It's a rather dumb tool, which doesn't cross reference the file list with which of those files actually have an svn:keywords property including Revision in it, and it doesn't do any other keywords, but people that want that kind of thing might at least grab this as a starting point. Cheers!

2010-01-12

In attempting to put HTML5 storage to use for cross-window configuration synchronization purposes, I just performed some tests on what works how in different browsers, and how it relates to the not-yet-frozen HTML5 specs, which at present declare that storage events should work like this:

On changing a value in localStorage (running localStorage.setItem(), localStorage.removeItem(), or localStorage.clear(), and presumably their javascript setter / deletion conveinence API:s, where supported), an e.type === "storage" event should be fired in all other windows open to the same domain (e here being the event object seen by the event listener). (No specific mention forbids firing the same event in the same window, too, but it seems to be the intent to avoid that, to me, and is also the behaviour I would prefer myself.)

When an assignment (localStorage.setItem()), the e.key property should be the name of the key, the e.oldValue its former value, and e.newValue its new value.

When a deletion (localStorage.removeItem()), e.newValue should instead be the null value.

When a clear all event (localStorage.clear()), e.key, e.oldValue and e.newValue should all be the null value.

No browser seems to do quite that yet, but Safari and Chrome are at least rather close. My tests have covered Firefox 3.5.7, Safari 4.0.4 (6531.21.10), WebKit 4.0.4 (6531.21.10, r53119), Google Chrome 4.0.249.49 (35163) beta, Chromium 4.0.267.0 (34084), all on MacOS X (10.6). They all ignore which window triggered the storage event (= fire the event in all applicable windows).

Firefox, sadly, never provides either of the three properties mentioned above.

Chrome, Chromium, Safari and WebKit all provide all three, but instead of setting the e.key to null for the clear event, it gets set to the empty string. The rest works beautifully, though.

Neither browser fires events when deleting an already deleted value, but Firefox fires events when setting a property to the same value it already had (the others don't).

I spent a minimal amount of time peeking at what IE8 does and how, but didn't get it working. It supposedly supports at least the localStorage function-calling API, according to MSDN. The tests above may miss something subtle, maybe with how to use attachEvent instead of the W3C standard addEventListener (don't ask me why they still don't support that).